A network or system comprises a plurality of entities, such as network nodes, electronic equipment, electronic elements or components, units, etc. During IP-network design, there will frequently be a need to assign a unique network entity identity number to some of the entities. If an entity has to be replaced, the new entity has to be provided with the unique network entity identity (ID) number. Said number is preferably provided by the network operator.
The most common solution to assign network entities a unique number is the use of a dipswitch, e.g. an eight bit dipswitch containing eight single switches, one for each bit. Each single switch could be set manually in either of two positions for indicating off-position, even denoted “0” (zero), or on-position, denoted as “1” (One). Said known solution is described in the following detailed description with reference to FIG. 1.
During entity restart, e.g. after power-up, the entity-processor reads the on/off position of each individual switch of the dipswitch and use this binary information as its entity network identity number.
Known problems, when dipswitches and other solutions are used for assigning a unique network entity ID number to an entity, are:                Limited space on a Printed Circuit Board (PCB). A dipswitch and corresponding components are relatively big components which will reduce the possibility to design really high density products. Specially in high density products this will also increase the Unit cost.        Required external access. To be able to set a dipswitch it is necessary to provide an opening in the unit casing for the operators, service and installation personal. The gating will often require a more complex mechanic production process and increase the Unit cost.        Electro-Static Discharge (ESD) protection of the entity is needed when a person access the interior of the external casing of the entity for setting the entity ID number. ESD protection circuitry requires both components and PCB-area. Especially the protection components will increase the Unit cost.        
Today this requirement concerning assigning a unique number to each entity also apply even for relatively small entities like a 12 or 24 subscriber line IP-units. These units are high volume products and very cost sensitive.